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1.
Anal Chem ; 96(1): 170-178, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38155534

RESUMO

Characterization of the elemental distribution of samples with rough surfaces has been strongly desired for the analysis of various natural and artificial materials. Particularly for pristine and rare analytes with micrometer sizes embedded on specimen surfaces, non-invasive and matrix effect-free analysis is required without surface polishing treatment. To satisfy these requirements, we proposed a new method employing the sequential combination of two imaging modalities, i.e., microenergy-dispersive X-ray fluorescence (micro-XRF) and Raman micro-spectroscopy. The applicability of the developed method is tested by the quantitative analysis of cation composition in micrometer-sized carbonate grains on the surfaces of intact particles sampled directly from the asteroid Ryugu. The first step of micro-XRF imaging enabled a quick search for the sparsely scattered and micrometer-sized carbonates by the codistributions of Ca2+ and Mn2+ on the Mg2+- and Fe2+-rich phyllosilicate matrix. The following step of Raman micro-spectroscopy probed the carbonate grains and analyzed their cation composition (Ca2+, Mg2+, and Fe2+ + Mn2+) in a matrix effect-free manner via the systematic Raman shifts of the lattice modes. The carbonates were basically assigned to ferroan dolomite bearing a considerable amount of Fe2+ + Mn2+ at around 10 atom %. These results are in good accordance with the assignments reported by scanning electron microscopy-energy-dispersive X-ray spectroscopy, where the thin-sectioned and surface-polished Ryugu particles were applicable. The proposed method requires neither sectioning nor surface polishing; hence, it can be applied to the remote sensing apparatus on spacecrafts and planetary rovers. Furthermore, the non-invasive and matrix effect-free characterization will provide a reliable analytical tool for quantitative analysis of the elemental distribution on the samples with surface roughness and chemical heterogeneity at a micrometer scale, such as art paintings, traditional crafts with decorated shapes, as well as sands and rocks with complex morphologies in nature.

2.
Sci Adv ; 9(45): eadi7048, 2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-37939187

RESUMO

Studies of material returned from Cb asteroid Ryugu have revealed considerable mineralogical and chemical heterogeneity, stemming primarily from brecciation and aqueous alteration. Isotopic anomalies could have also been affected by delivery of exogenous clasts and aqueous mobilization of soluble elements. Here, we show that isotopic anomalies for mildly soluble Cr are highly variable in Ryugu and CI chondrites, whereas those of Ti are relatively uniform. This variation in Cr isotope ratios is most likely due to physicochemical fractionation between 54Cr-rich presolar nanoparticles and Cr-bearing secondary minerals at the millimeter-scale in the bulk samples, likely due to extensive aqueous alteration in their parent bodies that occurred [Formula: see text] after Solar System birth. In contrast, Ti isotopes were marginally affected by this process. Our results show that isotopic heterogeneities in asteroids are not all nebular or accretionary in nature but can also reflect element redistribution by water.

3.
Sci Adv ; 9(28): eadh1003, 2023 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-37450600

RESUMO

Preliminary analyses of asteroid Ryugu samples show kinship to aqueously altered CI (Ivuna-type) chondrites, suggesting similar origins. We report identification of C-rich, particularly primitive clasts in Ryugu samples that contain preserved presolar silicate grains and exceptional abundances of presolar SiC and isotopically anomalous organic matter. The high presolar silicate abundance (104 ppm) indicates that the clast escaped extensive alteration. The 5 to 10 times higher abundances of presolar SiC (~235 ppm), N-rich organic matter, organics with N isotopic anomalies (1.2%), and organics with C isotopic anomalies (0.2%) in the primitive clasts compared to bulk Ryugu suggest that the clasts formed in a unique part of the protoplanetary disk enriched in presolar materials. These clasts likely represent previously unsampled outer solar system material that accreted onto Ryugu after aqueous alteration ceased, consistent with Ryugu's rubble pile origin.


Assuntos
Carbono , Meteoroides , Carbono/análise , Sistema Solar , Silicatos
4.
Science ; 379(6634): eabn7850, 2023 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-35679354

RESUMO

Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples of the C-type asteroid (162173) Ryugu were retrieved by the Hayabusa2 spacecraft. We measured the mineralogy and bulk chemical and isotopic compositions of Ryugu samples. The samples are mainly composed of materials similar to those of carbonaceous chondrite meteorites, particularly the CI (Ivuna-type) group. The samples consist predominantly of minerals formed in aqueous fluid on a parent planetesimal. The primary minerals were altered by fluids at a temperature of 37° ± 10°C, about [Formula: see text] million (statistical) or [Formula: see text] million (systematic) years after the formation of the first solids in the Solar System. After aqueous alteration, the Ryugu samples were likely never heated above ~100°C. The samples have a chemical composition that more closely resembles that of the Sun's photosphere than other natural samples do.

5.
Sci Adv ; 8(46): eadd8141, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36264823

RESUMO

Little is known about the origin of the spectral diversity of asteroids and what it says about conditions in the protoplanetary disk. Here, we show that samples returned from Cb-type asteroid Ryugu have Fe isotopic anomalies indistinguishable from Ivuna-type (CI) chondrites, which are distinct from all other carbonaceous chondrites. Iron isotopes, therefore, demonstrate that Ryugu and CI chondrites formed in a reservoir that was different from the source regions of other carbonaceous asteroids. Growth and migration of the giant planets destabilized nearby planetesimals and ejected some inward to be implanted into the Main Belt. In this framework, most carbonaceous chondrites may have originated from regions around the birthplaces of Jupiter and Saturn, while the distinct isotopic composition of CI chondrites and Ryugu may reflect their formation further away in the disk, owing their presence in the inner Solar System to excitation by Uranus and Neptune.

6.
Metallomics ; 13(4)2021 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-33693839

RESUMO

We performed micro-X-ray fluorescence imaging of frozen-hydrated sections of a root of Pteris vittata for the first time, to the best of our knowledge, to reveal the mechanism of arsenic (As) uptake. The As distribution was successfully visualized in cross sections of different parts of the root, which showed that (i) the major pathway of As uptake changes from symplastic to apoplastic transport in the direction of root growth, and (ii) As and K have different mobilities around the stele before xylem loading, despite their similar distributions outside the stele in the cross sections. These data can reasonably explain As reduction, axially observed around the root tip in the direction of root growth and radially observed in the endodermis in the cross sections, as a consequence of the incorporation of As into the cells or symplast of the root. In addition, previous observations of As species in the midrib can be reconciled by ascribing a reduction capacity to the root cells, which implies that As reduction mechanisms at the cellular level may be an important control on the peculiar root-to-shoot transport of As in P. vittata.


Assuntos
Arsênio/análise , Imagem Óptica/métodos , Raízes de Plantas/metabolismo , Pteris/metabolismo , Poluentes do Solo/análise , Espectrometria por Raios X/métodos , Síncrotrons/instrumentação , Biodegradação Ambiental
7.
Metallomics ; 12(2): 193-203, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31845691

RESUMO

The striking sub-cellular distribution of cadmium (Cd) and zinc (Zn) in the Cd and Zn hyperaccumulator Arabidopsis halleri ssp. gemmifera was revealed by microbeam X-ray microfluorescence analysis (µ-XRF) using high-energy synchrotron radiation. Plants were grown in hydroponics with various Cd and Zn concentrations. The concentration of Cd in the aerial portions of the plants increased with increasing Zn exposure and the transportation efficiency of Cd from the root to the shoot was affected by both the Cd and Zn concentrations in the nutrient solution. The µ-XRF imaging clearly showed that Cd and Zn were preferentially accumulated in trichomes on the leaf, while the distribution of Cd in the leaf was changed by Zn treatment. It was observed that Cd treated with a higher Zn concentration (20 µM Cd + 100 µM Zn) was distributed in the mesophyll tissue at high concentrations. In addition, µ-XRF imaging clarified that the distribution of Zn inside the leaf was different from that of Cd at a cellular level. Zn was primarily distributed in the mesophyll tissue of the leaf blade. In contrast, Cd was localized in the vascular bundle of the main vein. That is, Zn was transported to mesophyll tissue from the vascular bundle more efficiently than Cd. As seen above, we were able to study the difference of the distribution of Cd and Zn, which are congeners and behave similarly, inside the plant body at the cellular level in detail by high-energy µ-XRF.


Assuntos
Arabidopsis/metabolismo , Cádmio/metabolismo , Zinco/metabolismo , Arabidopsis/química , Cádmio/análise , Hidroponia , Folhas de Planta/química , Folhas de Planta/metabolismo , Raízes de Plantas/química , Raízes de Plantas/metabolismo , Espectrometria por Raios X , Síncrotrons , Zinco/análise
8.
Anal Chem ; 86(17): 8521-5, 2014 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-25084242

RESUMO

Synchrotron radiation (SR) X-ray microbeam analyses revealed the detailed chemical nature of radioactive aerosol microparticles emitted during the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, resulting in better understanding of what occurred in the plant during the early stages of the accident. Three spherical microparticles (∼2 µm, diameter) containing radioactive Cs were found in aerosol samples collected on March 14th and 15th, 2011, in Tsukuba, 172 km southwest of the FDNPP. SR-µ-X-ray fluorescence analysis detected the following 10 heavy elements in all three particles: Fe, Zn, Rb, Zr, Mo, Sn, Sb, Te, Cs, and Ba. In addition, U was found for the first time in two of the particles, further confirmed by U L-edge X-ray absorption near-edge structure (XANES) spectra, implying that U fuel and its fission products were contained in these particles along with radioactive Cs. These results strongly suggest that the FDNPP was damaged sufficiently to emit U fuel and fission products outside the containment vessel as aerosol particles. SR-µ-XANES spectra of Fe, Zn, Mo, and Sn K-edges for the individual particles revealed that they were present at high oxidation states, i.e., Fe(3+), Zn(2+), Mo(6+), and Sn(4+) in the glass matrix, confirmed by SR-µ-X-ray diffraction analysis. These radioactive materials in a glassy state may remain in the environment longer than those emitted as water-soluble radioactive Cs aerosol particles.

9.
Food Chem ; 147: 318-26, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24206725

RESUMO

Trace elemental analysis of soybeans was performed using X-ray fluorescence (XRF) analysis in order to characterise the geographical origins of the beans. By optimising the measurement conditions of an energy-dispersive XRF spectrometer equipped with three-dimensional polarisation optics, determination of trace elements at the sub-µgg(-1) level in soybean samples was accomplished. Forty-six samples were analysed. Results showed that there were some differences between the trace element contents, reflecting a difference in their geographical origins. A statistical analysis showed that the concentrations of eight elements (Mg, P, Cl, K, Mn, Cu, Br, and Ba) are good parameters for constructing a discriminant function for geographical origin. In conclusion, we were able to accurately distinguish between domestic and imported soybeans. The present work demonstrates that XRF is useful as a rapid and simple tool for provenance analyses of agricultural products.


Assuntos
Glycine max/química , Espectrometria por Raios X/métodos , Oligoelementos/análise , Análise Discriminante , Geografia
10.
Inorg Chem ; 51(11): 6211-20, 2012 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-22626447

RESUMO

Layered NaNi(0.5)Mn(0.5)O(2) (space group: R ̅3m), having an O3-type (α-NaFeO(2) type) structure according to the Delmas' notation, is prepared by a solid-state method. The electrochemical reactivity of NaNi(0.5)Mn(0.5)O(2) is examined in an aprotic sodium cell at room temperature. The NaNi(0.5)Mn(0.5)O(2) electrodes can deliver ca. 105-125 mAh g(-1) at rates of 240-4.8 mA g(-1) in the voltage range of 2.2-3.8 V and show 75% of the initial reversible capacity after 50 charge/discharge cycling tests. In the voltage range of 2.2-4.5 V, a higher reversible capacity of 185 mAh g(-1) is achieved; however, its reversibility is insufficient because of the significant expansion of interslab space by charging to 4.5 V versus sodium. The reversbility is improved by adding fluoroethylene carbonate into the electrolyte solution. The structural transition mechanism of Na(1-x)Ni(0.5)Mn(0.5)O(2) is also examined by an ex situ X-ray diffraction method combined with X-ray absorption spectroscopy (XAS). The staking sequence of the [Ni(0.5)Mn(0.5)]O(2) slabs changes progressively as sodium ions are extracted from the crystal lattice. It is observed that the original O3 phase transforms into the O'3, P3, P'3, and P3" phases during sodium extraction. XAS measurement proves that NaNi(0.5)Mn(0.5)O(2) consists of divalent nickel and tetravalent manganese ions. As sodium ions are extracted from the oxide to form Na(1-x)Ni(0.5)Mn(0.5)O(2), nickel ions are oxidized to the trivalent state, while the manganese ions are electrochemically inactive as the tetravalent state.

11.
Forensic Sci Int ; 220(1-3): 33-49, 2012 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-22445767

RESUMO

We have started the construction of a nationwide forensic soil sediment database for Japan based on the heavy mineral and trace heavy element compositions of stream sediments collected at 3024 points all over Japan obtained by high-resolution synchrotron X-ray powder diffraction (SR-XRD) and high-energy synchrotron X-ray fluorescence analysis (HE-SR-XRF). In this study, the performance of both techniques was demonstrated by analyzing soil sediments from two different geological regions, the Kofu and Chiba regions in Kanto province, to construct database that can be applied in the future to provenance analysis of soil evidence from a crime scene. The sediments from the quaternary volcanic lithology of the Chiba region were found to be dominated by heavy minerals of volcanic origin - orthopyroxene, clinopyroxene, and amphibole, and the REEs (rare earth elements) within the region showed similar geochemical behavior. On the other hand, four distinct heavy mineral groups were identified in the sediments of the Kofu region, where there is a great variety of underlying bedrock, and the geochemical behavior of the REEs in the sediments also varied accordingly to their geological origins. As such, our study shows that high-resolution SR-XRD data can provide information on the spatial distribution patterns of heavy minerals in stream sediments, playing an important role in determining their likely geographical origin. Meanwhile, the highly sensitive HE-SR-XRF data allow us to study the geochemical behavior of trace heavy elements, especially the REEs in the sediments, providing additional support to further constrain the likely geographical origin of the sediments determined by heavy minerals.

12.
Metallomics ; 3(12): 1340-6, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21969005

RESUMO

Trees that accumulate metals are important plants for restoring contaminated soil because of their high biomass. In our previous study, we discovered that Salix miyabeana has the capability to take up high levels of Cd, and identified the several accumulation sites of the endogenous metals in the leaf parts of plants. To analyze the detailed localization of Cd in apoplastic and symplastic compartments in S. miyabeana, synchrotron radiation-based micro X-ray fluorescence (SR-µ-XRF) analysis and micro X-ray absorption near edge structure (µ-XANES) measurements were performed on beam line 37XU of the SPring-8 (Hyogo, Japan). The two-dimensional metal distribution of segments of young stems was obtained by µ-XRF with approximately 2 µm(2) X-ray beams and showed the predominant localization of Cd in the apoplastic region. µ-XANES analyses suggest that the apoplastic detoxification of Cd in willow depends on Cd-oxygen, but not on Cd-sulfur, interaction. S. miyabeana growing near an old mining site in Japan was then examined to evaluate the metal accumulating ability of this plant in the field. The metal concentration in the leaves of the plants was compared to that in the soil and enrichment factors (EFs) were calculated for Cu, Zn, Cd and Pb. Results showed efficient removal of Cd and Zn from the contaminated sites by the willow plants. In order to discuss the combined and long-term effect of multiple heavy metals on S. miyabeana grown in soil, variable-pressure scanning electron microscopy fitted with energy dispersive X-ray analysis (VPSEM-EDX) and SR-µ-XRF was used to characterize the serration of leaves. The combination of 2D elemental images revealed metal accumulation in the tip cells in serrations without any exudation of heavy metals from the hydathodes.


Assuntos
Poluentes Ambientais/análise , Metais Pesados/análise , Folhas de Planta/química , Salix/química , Biodegradação Ambiental , Poluentes Ambientais/metabolismo , Metais Pesados/metabolismo , Folhas de Planta/metabolismo , Caules de Planta/química , Caules de Planta/metabolismo , Salix/metabolismo , Espectrometria por Raios X , Madeira/química , Madeira/metabolismo
13.
J Environ Monit ; 13(6): 1678-86, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21491037

RESUMO

The chemical form of Ag in the livers of five species of marine mammals was examined using X-ray absorption fine structure (XAFS) and X-ray fluorescence (XRF) spectroscopies. The XAFS analysis suggested that Ag(2)Se was present in the livers of the Franciscana dolphin (Pontoporia blainvillei), Dall's porpoise (Phocoenoides dalli), and Baird's beaked whale (Berardius bairdii), whereas Ag(2)S was present in the livers of the striped dolphin (Stenella coeruleoalba) and pygmy killer whale (Feresa attenuata). XRF spectroscopy results revealed that the distribution patterns of Ag and Se in a thin section of the liver of the Franciscana dolphin were the same; this also implied that Ag was associated with Se in the liver. Thus, the interaction of Ag with Se or S may offer significant protection against the toxicity of Ag in marine mammals. The formation of either Ag(2)Se or Ag(2)S might depend on the Hg levels in the liver. Ag(2)Se was observed in liver samples with relatively high Ag/Hg ratio, whereas liver samples with low Ag/Hg ratio contained Ag(2)S.


Assuntos
Golfinhos/metabolismo , Fígado/química , Prata/análise , Poluentes Químicos da Água/análise , Baleias/metabolismo , Animais , Feminino , Fígado/metabolismo , Masculino , Selênio/química , Prata/química , Prata/metabolismo , Espectrometria por Raios X , Enxofre/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/metabolismo , Espectroscopia por Absorção de Raios X
14.
Metallomics ; 3(7): 719-25, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21468440

RESUMO

Marine mammals accumulate mercury in their tissues at high concentration and detoxify by forming mercury selenide (HgSe, tiemannite) mainly in the liver. We investigated the possibility of formation of HgSe in various tissues (liver, kidney, lung, spleen, pancreas, muscle and brain) other than the liver of the striped dolphin (Stenella coeruleoalba). We applied a combination method of micro-X-ray fluorescence (µ-XRF) imaging and micro-X-ray diffraction (µ-XRD) using a synchrotron radiation X-ray microbeam to analyze the tissue samples directly with minimal sample preparation. By this method, many accumulation points for Hg and Se on a micron scale were found in thin sections of the spleen and liver tissue and consequently, the XRF spectra and the XRD pattern of the hot spots confirmed the presence of tiemannite, HgSe. On the other hand, the insoluble fractions after enzyme digestion of the nuclear and mitochondrial fractions of all tissues were subjected to X-ray absorption fine structure (XAFS) analysis. XAFS analysis confirmed the presence of HgSe in all the tissues examined (liver, kidney, lung, spleen, pancreas, muscle and brain) of the striped dolphin. The presence of HgSe in all the tissues examined suggests that Se would be involved in the detoxification process of Hg in various tissues other than the liver. This contribution seems to be large especially in the liver and spleen but relatively small in the kidney, pancreas and brain, because the proportion of insoluble fraction containing HgSe was lower in these tissues (25 to 46%). This is the first report on the presence of tiemannite HgSe in various tissues of marine mammals.


Assuntos
Monitoramento Ambiental , Compostos de Mercúrio/metabolismo , Especificidade de Órgãos , Compostos de Selênio/metabolismo , Espectrometria por Raios X , Stenella/metabolismo , Difração de Raios X , Animais , Análise de Fourier , Masculino , Mercúrio/metabolismo , Selênio/metabolismo , Distribuição Tecidual , Espectroscopia por Absorção de Raios X
15.
J Am Chem Soc ; 133(12): 4404-19, 2011 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-21375288

RESUMO

Lithium-excess manganese layered oxides, which are commonly described by the chemical formula zLi(2)MnO(3)-(1-z)LiMeO(2) (Me = Co, Ni, Mn, etc.), are of great importance as positive electrode materials for rechargeable lithium batteries. In this Article, Li(x)Co(0.13)Ni(0.13)Mn(0.54)O(2-δ) samples are prepared from Li(1.2)Ni(0.13)Co(0.13)Mn(0.54)O(2) (or 0.5Li(2)MnO(3)-0.5LiCo(1/3)Ni(1/3)Mn(1/3)O(2)) by an electrochemical oxidation/reduction process in an electrochemical cell to study a reaction mechanism in detail before and after charging across a voltage plateau at 4.5 V vs Li/Li(+). Changes of the bulk and surface structures are examined by synchrotron X-ray diffraction (SXRD), X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectroscopy (SIMS). SXRD data show that simultaneous oxygen and lithium removal at the voltage plateau upon initial charge causes the structural rearrangement, including a cation migration process from metal to lithium layers, which is also supported by XAS. This is consistent with the mechanism proposed in the literature related to the Li-excess manganese layered oxides. Oxygen removal associated with the initial charge on the high voltage plateau causes oxygen molecule generation in the electrochemical cells. The oxygen molecules in the cell are electrochemically reduced in the subsequent discharge below 3.0 V, leading to the extra capacity. Surface analysis confirms the formation of the oxygen containing species, such as lithium carbonate, which accumulates on the electrode surface. The oxygen containing species are electrochemically decomposed upon second charge above 4.0 V. The results suggest that, in addition to the conventional transition metal redox reactions, at least some of the reversible capacity for the Li-excess manganese layered oxides originates from the electrochemical redox reaction of the oxygen molecules at the electrode surface.

16.
Metallomics ; 2(4): 261-70, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21069168

RESUMO

In vivo X-ray analysis utilizing synchrotron radiation was performed to investigate the distribution and oxidation state of arsenic in the gametophytes of two hyperaccumulators, Pteris vittata L. and Pteris cretica L., and an arsenic-accumulating fern, Athyrium yokoscense in the several growth stages from germination. The distribution of arsenic in P. vittata changed through the development of the plant tissues as follows. In two-week-old gametophyte, arsenic was mainly present along the rhizoid. In the one-month-old gametophyte with reproductive organs, arsenic was accumulating uniformly in the sheet of cells, except in the reproductive area. After fertilization, arsenic was observed in the aboveground part of the sporophyte structures. P. cretica and A. yokoscense showed different distributions, respectively. P. cretica showed an accumulation of arsenic in the reproductive area, in contrast to P. vittata, before fertilization, while arsenic was observed in the aboveground part of the sporophyte after fertilization. A. yokoscense showed an accumulation of arsenic along the rhizoids before fertilization, while it was present mainly along the roots of the sporophyte after fertilization. Reduced arsenic (As(iii)) was observed in all stages and in all tissues of P. vittata gametophytes. Further, a reduction of arsenic was commonly observed among the three ferns, although arsenic was bounded to sulfur in A. yokoscense. These findings may be related to their own reproductive process or to detoxification mechanism. They provide basic information for the understanding of arsenic hyperaccumulation in these ferns, leading to further application of these gametophyte systems.


Assuntos
Arsênio/química , Gleiquênias/química , Células Germinativas Vegetais/química , Espectrometria por Raios X/métodos , Síncrotrons , Espectroscopia por Absorção de Raios X/métodos , Biodegradação Ambiental , Pteris/química
17.
Plant Cell Physiol ; 51(5): 848-53, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20378764

RESUMO

Trees that accumulate metals are important plants for restoring contaminated soil because of their high biomass. We examined the cadmium (Cd) tolerance and growth rate of six willow (Salix) species common in Japan. To characterize in detail the localization of Cd and its ligands, synchrotron radiation-based micro X-ray fluorescence analysis was used. This revealed the accumulation of cadmium at the tips of the serrations in leaves, and the phellogen and/or the phelloderm under the stem surface. micro-X-ray absorption near edge structure spectra of Cd in all the accumulation sites were similar to that of the Cd ion coordinated by O ligands in S. gilgiana.


Assuntos
Cádmio/metabolismo , Microanálise por Sonda Eletrônica , Salix/metabolismo , Fluorescência , Folhas de Planta/química , Caules de Planta/química , Síncrotrons
18.
Anal Bioanal Chem ; 395(7): 1987-96, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19789857

RESUMO

Blue-painted pottery was produced in the New Kingdom, Egypt, and decorated with blue, red, and black pigment. In this study, two newly developed portable instruments, a portable X-ray fluorescence spectrometer and a portable X-ray powder diffractometer, were brought to the site on the outcrop at Northwest Saqqara, an archaeological site in Egypt, to verify their performance in on-site analysis of excavated artifacts at the site. Pigments used for the blue-painted pottery and plasters in the New Kingdom were analyzed by these instruments on the basis of both their chemical compositions and crystal-structural information. The blue pigments were identified as two different pigments, Egyptian blue and cobalt blue. The diffraction pattern of the blue pigment of the painted pottery exhibited that of spinel structure. The XRF spectrum of the blue pigment obtained by the same instrument from the same position indicates the presence of Mn, Co, Fe, Ni, and Zn. The possibility of compositional transitions of the cobalt blue pigment with time was revealed on by detailed analysis of the XRF data. The reason for the transitions is considered together with the archaeological background of the New Kingdom, Egypt.

19.
J Forensic Sci ; 54(3): 564-70, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19302400

RESUMO

High-energy synchrotron radiation x-ray fluorescence spectrometry (SR-XRF) utilizing 116 keV x-rays was used to characterize titanium dioxide pigments (rutile) and automotive white paint fragments for forensic examination. The technique allowed analysis of K lines of 9 trace elements in 18 titanium dioxide pigments (rutile), and 10 trace elements in finish coat layers of seven automotive white paint fragments. High-field strength elements (HFSE) were found to strongly reflect the origin of the titanium dioxide (TiO(2)) pigments, and could be used as effective parameters for discrimination and classification of the pigments and paint fragments. A pairwise comparison of the finish coat layers of seven automotive white paint fragments was performed. The trace elements in the finish coat layers detected by the high-energy SR-XRF were especially effective for identification. By introducing the trace element information of primer and electrocoat layers, all the automotive white paint fragments could be discriminated by this technique.

20.
J Electron Microsc (Tokyo) ; 58(1): 1-6, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19150970

RESUMO

Nanosheets can be used as building blocks to fabricate versatile nanostructured materials. In this paper, morphology of the Cs(4)W(11)O(36) and Nb(3)O(8) and TaO(3) sheets with different layers are analyzed by different field-emission scanning electron microscopes (FE-SEMs). Chemical composition of the single-layered Cs(4)W(11)O(36) with thickness of about 2 nm, and multilayered Nb(3)O(8) nanosheets with thickness of less than 14 nm are analyzed by both the Si(Li) solid-state detector and transition edge sensor (TES) microcalorimeter, successfully. The effects of energy resolution, accelerating voltage and substrate on the quantitative analysis are discussed briefly.

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